Fire-tube boiler.



No. 880,672. PATENTED MAR. 3, 1908.

G. KOCH. FIRE TUBE BOILER.

APPLIOATION' PI LED HAY 6,1907.

ZSHEETS-SHEET 1.

Wi/fTlfSJtS Iwvewior PATENTED MAR. 3, 1908.

G. KOCH. FIRE TUBE BOILER. APPLICATION FILED MAY6,19Q7.

2 SHBETB-SHEET 2.

fibr n v THE NORRIS I'ETERS 60.. WASHINGTON. n. c.

GEORG KOOI-I, OF LAUSIGK, GERMANY.

FIRE-TUBE BOILER.

Specification of Letters Patent.

Patented March 3, 1908.

Application filed May 6.1907. Serial No. 372.146.

T 0 all whom it may concern:

Be it known that I, GEoRe Kocn, a subject of the King of Saxony, residing at Lausigk, in Saxony, Germany, have invented a certain new and useful Improvement in Fire- Tube Boilers, of which the following is a specification.

This invention relates to a fire-tube boiler having tubes which are surrounded by water and connect the fire-tubes to a flue, the heat ing gases traversing the superposed firetubes in the known manner in a sinuous ascending path.

The invention consists in the first place in closing the fire-tubes behind the connecting tubes by covers against which the water impinges. This arrangement prevents, at the points where the direction of flow of the gases is altered, the transfer of heat from the said gases to the boiler-wall in contact with the outer air; all the heat lost by the gases is transferred to the water.

The invention also consists in part in making the fire-tubes taper towards orifices which open in the direction opposed to the direction of the draft, so that through these orifices access can be had to the tubes for cleaning purposes to enable soot and ash to be removed from the fire-tubes without interrupting the working of the boiler.

A construction embodying the invention is shown in the annexed drawing, in which Figure 1 is a longitudinal section of the boiler and Fig. 2 a cross-section.

The superposed firetubes 1), 5 n, n and n, which constitute the fire fiues, are connected to each other in the known manner by means of tubes 9 surrounded by the water in the boiler. In order that at the points where the gases change their direction of flow and give ofi most heat, there is no loss of heat available for evaporating purposes, each fire-tube is provided, a short distance beyond the junction of the respective tube g, with a cover or diaphragm h, behind which is formed a water-chamber i, communicating by means of orifices 1c with the water-space of the boiler. It is preferable to have a continuation of the tube behind the diaphragm h, forming the chamber i, instead of making the tube terminate at the diaphragm, since in the former case the tube can be made to extend from one end of the boiler to the other, and can be riveted at each end, so that all the parts are interconnected. The tubes 9 which connect the fire-tubes b of the lower drum a to the fire-tubes n of the upper drum 1? are surrounded in the usual manner by the tubes 0 connecting the two drums, and are, therefore, also surrounded by water.

Instead of using tubes b, 12 n, and n extending from one end of the boiler to the other, the tubes may be made to terminate at the covers it, so that the chambers i are dispensed with. At the ends farthest from the diaphragms h, namely, at the ends from which the gases flow towards the diaphragms, the tubes 5 n, and n lead through the boiler-wall to the exterior of the boiler and are closed by doors or shutters m. Since the orifices closed by these doors open in the direction opposed to the direction of flow of the gases of combustion, the flame-tubes can be cleaned while the boiler is working. Preferably the tubes are tapered towards these orifices, to prevent theentrance of cold air. For cleansing the firetubes, hooks or bars are thrust through them, so that the deposits therein are caused to drop through tubes 9 into the fire-tubes below, until they reach the tubes p leading out of the boiler from the bottom of the lower drum.

Behind the fire-bars d in the fire-tube b, and directly adjacent the said bars, there is a massive block 1' of iron or other suitable metal extending to the orifice of the fire-tube, the flat upper-surface of the said block forming a continuation of the grate, and the under-surface of the block being convex to fit the fire-tube. During the working of the boiler the incandescent residues of combustion are gradually pushed along the surface of this block by the action of stoking, until they arrive near the rear end of the tube 1) and drop through the tube 10 from which they can be easily removed in a cooled state by moving the slide 8. The heated surface of the block 1' causes the combustion to be as complete as possible. Owing to the presence of the block the stoking and raking requires very little time, and the loss of heat involved thereby, and the consequent cooling of the boiler, are reduced. The passage of gases of combustion into the boiler-house during the stoking is prevented.

The dimensions of the block, more particularly its thickness and volume, must be in such relation to the grate-surface and fuel that the upper surface of the block stores as much heat as is required to maintain the erated. On the other hand the amount of heat retained by the block must not be sufficient to produce injurious distortion thereof.

In order to retain the proper dimensions and keep the quantity of heat transferred from the block to the adjacent tube-wall at a con v stant value, the entrance of flying ash between the tube and the surface of the block is prevented by bedding the block on a-thin layer 7" of metal filings.

Changes in the dimensions of the block can be effected within certain limits by raising or lowering the grate in the tube, or by inclining the fire-bars. The block 1' may consist of several parts.

What I claim as my invention and desire to secure by Letters Patent of the United States is 1. In a fire tube boiler of the nature described the combination with the fire tubes and connecting tubes of diaphragms in said fire tubes placed respectively beyond the connection of each fire tube with the connecting tube leading therefrom and water chambers behind said diaphragms.

2. In a fire tube boiler of the nature described the combination with the fire tubes and connecting tubes of diaphragms in said fire tubes placed respectively beyond the connection of each fire tube with the connecting tube leading therefrom and Water chambers behind said diaphragms formed by perforated continuations of the fire tubes.

3. In a fire tube boiler of the nature described the combination of fire tubes and connecting tubes diaphragms in the fire tubes placed respectively beyond the connection of each fire tube with the connecting tube leading therefrom, the opposite ends of said fire tubes being tapered and extending to the boiler Wall, and doors to said tapered ends.

In witness whereof I have signed this specification in the presence of two witnesses. 4

GEORG KOCH.

Witnesses HERM. LoUTz, RUDOLPH FRICKE. 

